The term adaptogen was introduced in scientific literature in the 1950s to refer to substances that increase the “state of non-specific resistance” under stress conditions (Lazarev, 1958
; Lazarev et al., 1959
). The adaptogen concept was based on the theory of stress (Selye, 1950
), initially defined as a state of threatened homeostasis, and a general adaptation syndrome characterized by a non-specific response of the organism to diverse stressors (physical, emotional, environmental, etc.). It has been postulated that adaptogens should be safe and are able to normalize body functions irrespective of the nature of stressors (Brekhman II and Dardymov, 1969
). On the verge of the new millennium, the definition of adaptogens was updated to “a new class of metabolic regulators which increase the ability of an organism to adapt to environmental factors and to avoid damage from such factors
” (Panossian et al., 1999a
). The concept of adaptogens is now generally accepted by the scientific community (EMEA/HMPC/102655/, 2007
; Samuelsson and Bohlin, 2009
), although it has yet to gain prominence in mainstream pharmacology. In this context recent research progress has taken two main forms:
- Convincing clinical evidence has been generated on the efficacy of adaptogens, based on clinical trials performed in accordance with the International Conference in Harmonization Regulations (ICH) standards for good clinical practice (Davydov and Krikorian, 2000; Goulet and Dionne, 2005; Sarris, 2007; Bleakney, 2008; Panossian and Wikman, 2009, 2010; Dwyer et al., 2011; Hung et al., 2011; Iovieno et al., 2011; Sarris et al., 2011; Chan, 2012; Ishaque et al., 2012),
- Some key molecular mechanisms of adaptogen activity were defined (Panossian et al., 2007, 2009, 2012).
The stress-protective activity of adaptogens is associated with regulation of homeostasis both on:
- the system level via several mechanisms of action which are linked to the hypothalamic-pituitary-adrenal (HPA) axis, and the cellular level via activation of molecular chaperones, mainly hsp70 proteins, and the regulation of key mediators of the stress response, including neuropeptide Y (NPY), cortisol, nitric oxide, stress-activated protein kinase JNK, and forkhead box O transcription factor (Panossian et al., 2007, 2009, 2012; Wiegant et al., 2009).
An important role of CNS system in stress is generally accepted, since the stress concept has been defined by Selye (Fink, 2000
). Effect of adaptogens on CNS system, particularly neuroprotective activity has been demonstrated in many animal and human studies (Panossian and Wikman, 2010
; Panossian et al., 2011
). Clinical efficacy of adaptogens in behavioral and mental disorders such as depression, anxiety, bipolar disorder, chronic, and stress-induced fatigue has been recently reviewed (Panossian and Wikman, 2009
) is a traditional herbal medicinal product consisting of a fixed combination of extracts from Rhodiola rosea
root, Schisandra chinensis
berry, and Eleutherococcus senticosus
root. It is taken for decreased body performance such as fatigue and weakness (Bogatova et al., 1997
; Narimanian et al., 2005
; Aslanyan et al., 2010
). In general, herbal mixtures exert their bioactivities through synergistic interactions of single components. This synergism can be attributed to the fact that medicinal herbs contain many different phytochemicals, which may mutually influence each other’s activity. More than 140 compounds have been identified in R. rosea
roots (Panossian and Wikman, 2010
), 100 compounds in E. senticosus
roots (Huang et al., 2011
), and about 200 compounds in S. chinensis
berries (Panossian and Wikman, 2008
). Many of them were shown to be active in pharmacological in vivo
and in vitro
experiments, and likely contribute to the activity of the total extracts (Wagner et al., 1994
; Panossian, 2003
; Panossian and Wagner, 2005
; Panossian and Wikman, 2008
; Panossian et al., 2008
; Huang et al., 2011
). It has been shown that the adaptogenic activity of ADAPT-232 is associated with key mediators of stress response, e.g., heat-shock-proteins (Hsp70) and NPY, involved in the regulation of homeostasis, oxidative stress, energy metabolism, cognitive function, and activation of the immune system during fatigue and exhaustion (Prodius et al., 1997
; Panossian et al., 2009
). However, the cellular and molecular modes of action are not well understood due to the fact that herbal remedies in general have multiple targets and several mechanisms rather than a single mechanism may account for their pharmacological effects.
Any pharmacological effect represents an integrated response of an organism to the drug. The response can be associated with interactions between the drug and the cell at various levels of regulation:
- The level of a small physiologically active molecules, e.g., cAMP plays an important role in the integrative response of the organism. This is the so-called metabolomic level, because ATP is a precursor of cAMP and AMP is a metabolite.
- The level of proteins involved in the synthesis or degradation of ligands or ligand receptors. This is the so-called proteomics level of regulation.
- Genes encoding proteins involved in synthesis, degradation, signal reception, and regulation. This is the so-called genomic and transcriptional level of regulation.
Activation or suppression of gene expression results in activation or inhibition of the biosynthesis of encoded proteins (enzymes, cofactors, or receptors), which in turn affects the production and function of active small molecules. Gene expression profiles aid in tracing molecular interactions and signal transduction pathways and to predict the pharmacological effect a drug will have on various cellular functions.
Recently, the so-called “-omics” technologies have been established for the analysis of pharmacological effects (Ulrich-Merzenich et al., 2007
; Sarris et al., 2012
). Since transcriptomics and proteomics can monitor cellular changes in gene or protein expression upon drug treatment in a comprehensive fashion, these techniques may be exquisitely suited to investigate the multi-faceted mechanisms of herbal formulas. Therefore, we have analyzed the microarray-based transcriptome-wide mRNA expression profiles of the neuroglial cell line T98G after exposure to ADAPT-232 and its herbal components, R. rosea
, S. chinensis
, and E. senticosus
The choice of neuroblastoma cell line T98G for our study is based on results obtained in many publications (Stein, 1979
; Guzhova et al., 2001
; Su et al., 2012
). In the central nervous system, approximately 90% of the cells are glia. Glia has been shown to have several functions, including serving as a transportation link between the bloodstream and neurons, uptake of neurotransmitters, synthesis and release of neurotrophic factors, immune regulation, and modulation of synaptic activity (Henn and Hamberger, 1971
; Haydon, 2001
; Ullian et al., 2001
). Glia contributes to the defense of the brain through the expression of the innate immune response, promoting the clearance of neurotoxic proteins and apoptotic cells from the CNS as well as by regulating the entry of inflammatory systemic cells into the brain at the blood-brain barrier (Nguyen et al., 2002
; Hauwel et al., 2005
). This stimulates both tissue repair and the rapid restoration of tissue homeostasis. An important physiological function of neuroglial cells is metabolic supply of energy and other substances, maintaining brain homeostasis – a function supposed to be the characteristic for adaptogens by definition. Glial cell express a variety of hormonal receptors, which are critical during stress-induced diseases. Glial cell express steroid receptors and generate many steroid hormones which elicit rapid non-genomic effects on neurons via both membrane-bound G-protein coupled receptors and nuclear genomic receptors known to activate RNA and protein synthesis (Bennett, 2000
). Guzhova et al. (2001
) show that glioma cells export Hsp70 into the culture medium whether under normal conditions or subjected to heat shock. Hsp70 can be released by glia and that exogenous Hsp70 can enhance neuronal stress tolerance (Guzhova et al., 2001
). Finally, an ability of astrocytes, but not neurons, to prevent macrophage and T-Cell inflammation in the CNS, to attenuate axonal loss and gliosis resulting in neuroprotection in experimental autoimmune encephalomyelitis, the most widely used mouse model of multiple sclerosis (Spencea et al., 2011
) was the reason to select neuroglia cells in our studies devoted to understand molecular mechanisms of action of adaptogens.
The aim of the investigation was to compare similarities and differences in gene expression profiles upon treatment with these three adaptogenic plants. We compared the two plant extracts ADAPT-232 and ADAPT-232 forte (which is the same composition as ADAPT-232 except also includes the anti-stress vitamin, calcium pantothenate). We also compared these two fixed-composition mixtures to individual active compounds isolated from these plants, namely, salidroside, triandrin, tyrosol, eleutheroside E, and schizandrin B (Figure ). This pharmacogenomic analysis facilitates increased understanding of the molecular modes of action of adaptogens and the synergism of ADAPT-232 forte.
Experimental setting for microarray-based transcriptome-wide mRNA profiling and 3D-HPLC fingerprint of ADAPT-232.